Tuberculosis (TB) patients with high d-dimer levels are 8 times more likely to develop venous thromboembolism (VTE), according to a study published in the December 2022 issue of The Clinical Respiratory Journal.¹ The risk was also higher in patients with fever, dyspnea and lower limb edema.

For this study, patients admitted to a Chest Hospital in China between January 2016 and January 2020, who had been diagnosed with TB were recruited. Patients with just a day’s hospitalization were not included in the trial. The aim of the study was firstly to determine the risk factors for VTE in patients with TB and secondly to evaluate the prognosis of those patients who had developed VTE. On retrospective analysis of data, 107 TB patients were found to have VTE. The control group consisted of 1:1 matched TB patients who did not have VTE. More than half (60.17%) of the study population was male.

The incidence of VTE in patients with TB in this study was 0.95%. While the average age of the participants was 62.2 years, those who developed VTE were older with median age 65.7 years vs 58.6 years (median) in those who did not have VTE. On univariate analysis, the likelihood of VTE was found to be higher among patients with fever, dyspnea, lower limb edema and active TB. TB patients with malignant tumor and respiratory failure showed a significant association with VTE.

When laboratory results were examined, patients with VTE had higher levels of PT, aPTT and d-dimer compared to the controls. The cut-off level for d-dimer was defined as 1855 μg/L. But, Hb was considerably lower in the VTE group than in the control group. No association of WBC and platelet counts were observed for VTE.  Likewise, the site of TB, pulmonary or extrapulmonary, had no effect on the risk of VTE. The risk of VTE was reduced among patients on rifamycin.

On multivariate logistic regression analysis, high d-dimer levels increased the risk of VTE by 8-folds with odds ratio of 8.84. The odds of VTE occurring increased nearly 5-folds in the presence of lower limb edema with OR 4.9. Patients with active TB were 16 times more likely to develop VTE (OR 16.2).

This study affirms the high risk of VTE in TB patients, who are in a hypercoagulable state. Additionally, it raises awareness about the risk factors for VTE in patients with TB and further highlights “the need for active prevention and treatment” of VTE. The risk was greater in patients with fever, dyspnea, lower limb edema, d-dimer level ≥1855 μg/L and active TB. Hence, TB patients with these risk factors should be screened and closely followed-up for VTE. If required, prophylactic anticoagulant therapy may be instituted to reduce the risk. “Effective directly observed treatment plus short-course chemotherapy (DOTS) protocol anti-TB therapy helps reduce the probability of VTE in TB patients”, concluded the authors.¹

Reference

1. Guo Yi Nan, et al. Risk factors associated with venous thromboembolism in tuberculosis: A case control study. Clin Respir J. 2022 Dec;16(12):835-841. doi: 10.1111/crj.13555.